Hi.....im wondering what most people consider boosting my STI V5....it comes standard with 17psi but do u reckon i can run 19psi safely regards AussieJoe

I can't give you a one-dimensional yes-no answer. Depends on a multitude of factors I am afraid.

Ambient temp, altitude, fuel quality, intake and exhaust gas temps, knock, ignition timing, injector duty cycle, intercooler efficiency, intended use, what ECU, and many more.

If you mean just yank it up without consideration of all these factors and without monitoring the answer is a definite no.